| 摘要 |
PURPOSE:To shorten a time necessary for determining the position of a head by constituting the titled device so that the loop gain of a positional control system is increased at an instance when operation shifts to the position control mode, then said gain is approached gradually to the normal value. CONSTITUTION:When a mode switch 2 is switched to a position control contacting point (b), an interlocked switch 2' also switches to a terminal (b), and a reference voltage Vc is applied to the differentiator 14 of a control means 10, thus differential signals Vx whose values are large immediately following the said switching but becomes smaller as time lapses are inputted to a multiplier 11. In case a position signal A is large in relation to a position deviation Xe, the multiplier 11 further multiplies a phase compensating signal C to increase the value of a correcting signal C'. Accordingly, an output signal B from a control means 10 becomes larger, hence a head tends to reach a targeted position faster, however, the closer the head approaches to the target position, the closer to zero the correcting signal C' comes, and so much the more an output signal B approaches the phase compensating signal C, when the loop gain just as the conventional can be obtained. |
